Are you gonna tell me shadow priest interrupt is important? lmao its 30 yards man and its not a ranges job to interrupt unless melee specifically cant.
ie; Elisande, which is why hunters with a 50 yard interrupt exist
VE is good, but not great, it should scale better with larger group sizes.
Everything else you said is mostly irrelevant, shamans should purge, our gcd's are far more valuable than theirs.
Mass dispel, is so niche there are only 2 fights ive ever seen it being important, Felmyst and Helya, it wont show up again, especially now that spriests are irrelevant enough for multiple raid positions.